Free online TAR.ZST to ISO converter

What the TAR.ZST format is

TAR.ZST is a TAR archive compressed with Zstandard, usually written as .tar.zst or .tzst. TAR stores multiple files and directories in one archive, while Zstandard reduces its size; TAR itself does not provide compression. Linux distributions, package builders, backup tools, and command-line users commonly create it with tar --zstd, zstd, or software that archives source trees and release files. You may encounter it when downloading Unix source code, software packages, system backups, or repository snapshots.

What the ISO format is

ISO is a sector-oriented disc-image format, most commonly containing an ISO 9660 filesystem. It is supported by optical-disc writers, operating-system mount tools, virtual machines, boot utilities, and many archival applications. An ISO is useful when software expects a mountable or writable disc image, but it does not automatically preserve every TAR feature such as Unix ownership, permissions, symbolic links, extended attributes, or hard links.

How to actually convert TAR.ZST to ISO

On Linux or macOS, install Zstandard and xorriso through your operating system's package manager. Create a destination directory and extract the archive:

mkdir extracted
 tar --zstd -xf archive.tar.zst -C extracted

If your TAR implementation does not support --zstd, use the decompressor in a pipeline:

zstd -dc archive.tar.zst | tar -xf - -C extracted

Build an ISO from the extracted directory with xorriso:

xorriso -as mkisofs -r -J -V ARCHIVE -o archive.iso extracted/

-r adds Rock Ridge metadata for Unix-like systems, -J adds Joliet names for Windows compatibility, -V sets the disc label, and -o specifies the output filename. The command creates a data ISO; it does not make the image bootable unless you also provide the required boot files and boot catalog options.

On Windows, 7-Zip can extract archive.tar.zst in two stages: open the Zstandard-compressed file to obtain the TAR archive, then open the TAR archive and extract its contents. Use an ISO authoring application that can create an image from a folder, select the extracted directory as the source, choose ISO 9660 with Joliet support when offered, and export it as archive.iso. You can also convert the file on 101convert.com for free without installing software; do not upload confidential backups or archives containing private data.

If the requirement is to preserve the original TAR.ZST unchanged inside a disc image, do not extract it. Create an ISO containing archive.tar.zst as a regular file instead; that preserves the archive's contents and metadata within TAR, while the outer ISO provides the required disc-image format.

Quality, compatibility, and limitations

Check the resulting image by mounting it or listing it before distribution:

mount -o loop archive.iso /mnt/test
find /mnt/test -type f

ISO 9660 has filename and path restrictions. Rock Ridge preserves longer Unix-style names on compatible systems, and Joliet improves Windows filename support, but neither reproduces all TAR metadata. Files with names that differ only by case, deep paths, symbolic links, device nodes, or special permissions require particular testing. Keep the original TAR.ZST alongside the ISO when exact Unix archive restoration matters.